This article is about specific risk control methods for chainsaw and chainsaw operations.
The saw blends many common safety features for many machine-driven power tools. Manufacturers have created many design features to improve safety. Some features have become de facto standard , and others are legal requirements in certain jurisdictions. Best practice states that the operator should check the saws before starting work and only operate the saws if all safety features work properly.
Additional safety features are a significant commercial advantage for the saw manufacturer. The company continues to develop new features from time to time. Most of the chainsaw security features are focused on bribe issues, and try to avoid them (chain and trunk design), or to reduce the risk of injury if it occurs (brake chain).
In addition to the security features built into chainsaws, operators must also wear special chainsaw safety clothes. Most older chainsaws have little or no of these features, and extra attention should be taken in their use.
Video Chainsaw safety features
Chain
The chain should fit perfectly with the guide and chainsaw blades. Chainsaw producers determine the choice of chains that are suitable for each saw model.
The best security requires the chain to be properly honed. One of the sharpening key parameters is the depth gauge setting. The depth meter is a small steel bulge in front of each cutting of the tooth. The height difference between the leading cutting edge and depth gauge determines the thickness of the wood chip taken by the cutter. If the depth gauge is too low, the cutter takes too deep a bite from the wood, the saw becomes difficult to control and the likelihood of the kickback increases.
Some chains also have a guard link in front of each cutter link. The safety connection reduces the leading edge tendency of the depth gauge to tear small diameter objects such as a small branch, or to engage with ordinary wood if forced to come into contact with it.
Maps Chainsaw safety features
Chainsaw Chainsaw
Kickback Reduction
Kickback is mainly caused by cutting with a chain in the "kickback zone" in the bar, the top of the nose. Some saws, usually electric saws intended for the use of domestic parks, protect this entire area from contact with "tip guard". All cuts produce a reaction force on the saw: usually this should be the bottom edge of the bar, where the chain moves toward the saws and the reaction tends to pull the saw safely towards the log, against the dog spur. Where the chain moves down, like at the other end of the bar, the same reaction strength is now acting upward and will cause upward bribe.
The tip guard is a metal or plastic device that fits over the end of the rod and is usually fitted to a small domestic class chainsaw. While this is effective, they inhibit chainsaws in terms of the type and cutting capacity that can be done, and are not widely used. They found useful apps in the one-handed polar and battery-powered trimmers and saws used for trimming, hedging, etc. A crooked nose from the protective end can be used to "take" twigs to be cut, and there is no great loss since the very small saw unit is not used for cutting where the end of the bar is buried.
Carving bar
Chainsaw carving often makes the use of accidentally piece plunging, and cutting off the end of the bar. By simply reducing the diameter of the nasal chain, the number of chains, and thus the force generated during kickback, can be reduced. Specialized engraving bar is available with a small pointed nose.
Chain brake
The chain brakes prevent the chain movement of chainsaw by applying the steel brake tape around the drum-driven drum. The force of the brace for the brake lining is provided by a strong spring. Brake chain has two goals. First, it can be used to secure a chain when changing position, moving between cuts or starting a chainsaw, which requires a partially open throttle. This will in turn lead to an uncontrolled movement of the chain, a great danger in older chainsaws. Second, the chainbrake can be activated under kickback conditions to prevent the operator from being hit by a running chain. Being beaten even by a static chain can cause serious injury, but anything that can be done to reduce the usually horrific injuries caused by contact with a moving chain is a great benefit to the operator. Back injuries usually occur on the head, face, neck and shoulders; when a chain run is involved, such injuries are usually very serious, often damaging and sometimes fatal.
The chain brake is principally operated by the upper hand guard pushed forward to activate the brake, and pulled back to disengage. This spring action allows strong braking in emergency situations and can stop the chain in full force in a split second. Correspondingly, it may require considerable strength to rearrange.
The chain brake can be activated by the operator intentionally, or automatically by the power of a dinging event. In the first, the operator usually twisted his left wrist and tapped the upper hand guard forward with the back of his hand, rearranging it again by reaching forward with his fingers to pull the guard up behind his hand. In the event of a dribble, the operator's left hand may be detached from the handle and the upper hand guard will be thrown into his hand, forcing the brake chain activation. The Husqvarna model also incorporates a link between the top grip and the chain brake trigger, applying the brakes if the forced saw bar is suddenly upward. This is known as "inertia congestion" and will allow brake chain activation even if the operator's left hand is not removed from the handle.
Chain brakes can also be used when sharpening chains in bars, as it allows powerful archiving to take place without a slip chain.
"Topping bodyguards" have appeared in recent years, but are not popular. They restrict movement, and do not allow concessions for the fact that when the handle is gripped at the bottom of the handle (the left side of the saw from the operator's point of view) is usually to make a lateral, right-to-left cut. In this situation the head of the carrier, neck and shoulders is outside the cutting area of ​​the saw and generally will not be thrown even if a ding occurs.
Chainsaw kickback
Chainsaw kickback can occur when the end of the bar comes into contact with a relatively massive or immovable object with a chain under power. The bar area most likely involved is known as the "kickback quarter". Looking at the side of the bar, the kickback quarter is the 90 ° bar that is found between the lines along the center line of the bar, and another line at 90 ° to the first, up from the center of the nasal sprocket. If this chain area is in contact with - for example - logs, the chain will initially cut wood, but it will also produce a reaction force that pushes the rod up. As the bar rises, the chain is forced harder in contact with the wood and climbs up harder. Within a split second, the chain may jam into the wood and throw the bar upward toward the operator, often causing severe injury or death. The hardness of a full dribble event is such that no circumvention is possible, and if the head of the operator, neck or shoulder matches the bar area, they will surely be hit by it. At this point, the operator must rely on brake chains and protective clothing to save him from injury or worse.
Another form of kickback may occur where the top of the bar is used to cut and is suddenly squeezed by the moving wood. In this case the saw can be pushed back toward the operator, or forced into a position where the tip is pinched and the saw transition becomes classic tip-driven tip. Kickbacks can also occur as a result of a boring cut that failed or was not implemented correctly. Drill cutting is a special technique that requires proper training, and should not be attempted without such training.
Kickback damping system
By far the most effective tool in preventing bribes is operator training. By preventing contact between the ends of the rod and solids, kickback can be avoided. By keeping their heads and bodies out of the bar's cutting area, injuries can be prevented if a kickback occurs. A useful tip is if the operator can not read the logo on the side of the bar, they are too close to the cutting field and should lean to the left to ensure safety.
Correct chain sharpening is essential for safety in this context. The blunt chain cuts out badly and leads to increased operator fatigue and increased loading of bars. The incorrectly inserted depth gauge makes the chain capture in the wood and can negate the benefits offered by the safety chain.
Chain design plays a major part in bite reduction. Older and insecure designs only use gauges and depth. Since this presents a leading edge in the depth gauge if an object is suddenly forced into a chain, they can easily be made to engage completely with a foreign object and launch into a full feed. Charging a careful depth meter, making the radius to the front edge, reduces risk. The newer chains with driven driving links fill the gap in front of the depth gauge, reducing the tendency to take it further. The full safety chain has an extra bumper connection between the cutter links, maintaining a near full height gauge throughout the chain completely and reducing the risk of bribe to very low levels. Bumpered chains are often installed as original equipment for saws inside and outside the home. Modern "professional" chains offer much higher cutting performance than full safety chains, and offset their increased risk with the assumption of a much higher level of operator competence. In fact they are still safer than traditional chains because of the design of a much better depth gauge, way ahead of the measuring point.
Bar design is another factor in reducing kickback risk. The larger the radius of the end of the bar, the greater the risk of kickback because the level of involvement with logs (or other entities) will be greater for larger tips. Domestic class bar, hiking bar, and beginner-level professional bar usually have very little tips. Professional bars designed for felling and logging may have a much bigger tip because it is often used for tedious cuts to free trapped wood or cut down difficult trees, and pointy little bars will easily clog up when boring, stretching out the chain. Large-pointed bars with almost parallel sides boring easily and do not tend to jam.
While kickback prevention is a big concern in the context of chainsaw usage, it is not the only way that can cause the operator to be hurt by a saw. Local conditions, operator competence and many other factors need to be considered before conducting a sawmill operation.
Chain catcher
The chain catcher helps prevent the chain being thrown back to the user, if the chain is broken or becomes slipped. The catcher catches the chain while detailing down and making it shorter. Then the chain moves under the body of the saw which crashes the back of the rear hand on the rear handle (The bottom of the handle is wider to the ba side like the others). As shown on the image chain catcher made of aluminum does not damage the chain. The outdated chain catcher can be changed.
Throttle security
Throttle machines are operated by a trigger under the rear saw handle. Unless the locking switch above the rear handle is also pressed, the throttle can not move from the stationary position, and the chain will not be moved.
The safety throttle prevents the chain from being pushed if the trigger is accidentally driven by obstruction, like a branch in the bush. It also prevents throttle activation when hot-starting saws on the ground with one boot inside the rear handle. Security throttle is an additional layer of protection in this case, since brake chains must be applied before starting a saw in any context.
The model depicted has an enlarged lock-out or 'dead man' button which, when released, also activates the chain brakes, thus instantly stopping the running chain and releasing the throttle.
On/Off button
In a gasoline-powered saw, the on/off switch stops the running engine by preventing the ignition coil from firing. This switch is also called a kill switch. It should be clearly marked with a stop position. There must be a positive click action, so there is no possibility that the switch will change position by mistake, even when the saw is vibrating under heavy load.
If the switch is moved to the off position while the operator is in the middle of critical cuts when cutting down trees, there will be at least a delay, which increases the likelihood that the tree falls in an uncontrolled manner. In addition, the chainsaw may be jammed at the cut, which requires the operator to spend extra time under an insecure tree so free it. The "active" switch will also pose a danger, since the saw can start inappropriately, such as when testing compression or assessing starter function.
If the operator is injured while using a saw, an observer may have to move to turn off the saw. The observer may be unfamiliar with the chainsaw and should be able to identify the on/off button with its markers.
The Stihl model is displayed incorporating the start choke, throttle and ignition switch settings into one integrated control lever. Other brands of chainsaws usually have separate controls for all three, or a combined start throttle setting and choke control with a separate ignition switch.
If the switch fails to operate, the saw can be stopped by operating the choke control to flood the machine.
Centrifugal clutch
The centrifugal clutch releases chains from the engine when the engine is only at idling speed, involving the drive automatically when the throttle is kneaded and the engine is at full speed. The purpose of this clutch is to avoid the moving chain when the saw is stopped and not cut temporarily. When idle, the chain should not move.
Many rear saws are used in the circumstances, because of poor maintenance, where there is some pull of the clutch and the chain moves slow when not in use. For top-handed saws, this is very dangerous and the clutch (and chain brakes) on the saw should always function properly.
Some early saws use manual clutches instead, but these have long been obsolete.
Anti-vibration system
Excessive vibrations for a long time may cause the user to develop a hand-arm (HAVS), or white finger-trap syndrome. This is a potentially permanent and debilitating industrial injury. To reduce vibration, saws are divided into two parts. One part is the rigid assembly of cutting machines and machines. This section vibrates strongly when the chain cuts off. The other part is the assembly of the handle and the rigid engine control, the part held by the user. These two rigid assemblies are united by mounts that produce spring suspension and damping.
Both metal springs and rubber bushes can be used to provide suspension. The metal springs are stronger and longer-lasting, but the rubber shrubs provide attenuation in addition to spring action.
Many modern saws incorporate electrically heated hoists. This can help prevent HAVS by encouraging circulation to the fingers. The Husqvarna model with this option has a "G" suffix after the model number and Dolmar sees "H".
Rear handle
The front and rear handles of the typical "rear saw" saws have large distances, providing sufficient leverage for good control, and also to provide multiple levels of control in the event of a kickback.
Sawing operation controls, such as throttle and engine stop (or on/off) switches, are positioned so that they can operate while maintaining a good grip on the rear handle.
It is impossible to use a hand-reared saw with one hand. Balance them in such a way that this is not simply unwise, but very impractical for being out of the plausible opportunity for it to even be attempted.
Top chainsaws
Top-handed saws are saws whose security is deliberately compromised to allow them to be used with a single hand where this is important. They are limited to work at altitude, as in trees. In all other cases, it should be possible to arrange cutting duties so that it can be done with two hands and chainsaws handled safely.
On the top hand saws, the rear grip and control of the operation are moved to the top of the saw. This provides a balance on the saw so that can now used with one hand. The front grip remains the same. Chain brake levers are usually separate, instead of coupled with protective hand protection.
In most cases, the top-handed saws are used with two hands. It is only used one hand when this is important, such as when one hand is required to climb. At ground level, the topmost handled saws should not be used.
Due to the nature of the work at altitude, and the difficulty of continuing to turn on the saws, the engines will often keep running when not in use for cutting at that moment. For this reason, it is essential that the centrifugal clutch operates properly so that the chain does not rotate when the machine is idle. Chain brakes should also be manually involved when they are not really needed, which is why the top-handed saws usually have an easy brake control lever.
In many jurisdictions, the use and even purchases of top-handed saws are limited to those holding competence certificates that are relevant in their use. But in the United States, such chainsaws can be bought and used freely.
Rear hand protection
The rear-hand shield protects the user's hand from choppy or disconnected chain attacks. This also allows the rear of the saw to be pressed by the boot operator to start. This is very useful for cold machines, and larger saws (70Ã, cc).
Handedness
The majority of chainsaws are designed for use by people who use the right hand. Using such chainsaws on the left is an additional security hazard. The left-handed person must learn to use it in the right hand way. No left-hand saws are produced.
Exhaust
The muffler directs the hot and dangerous gases that come from the engine away from the user. A damaged exhaust raises noise, lowers engine power, can expose users to an unsafe level of exhaust gases, and can increase the likelihood that the user may inadvertently touch a very hot metal. Most models feature a spark screen that is integrated into the exhaust. Splash screen prevents sparks regardless of disposal and potentially burns sawdust. The splash screen also reduces noise.
Hand/Eye/Ear Defender Symbol
In the EU at least, it is a legal requirement that chainsaws carry certain standard warning labels that warn of kickback hazards as well as clarify the need for protective clothing.
Scabbard
The cutting chain is sharp enough to cause injury even when not being pushed. The sheath covers the chains when the saw is in the shed or transported. It also protects the chain from damage, for example, by collecting contacts with concrete floors.
References
Source of the article : Wikipedia
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